Methane–air-premixed flames impinging on plane surfaces

Abstract

Determination of heat transfer characteristic has been analysed theoretically using the heat propagation phenomena of methane–air-premixed turbulent flames impinging on plane surfaces. The heat flux propagation on the plane surface completely depends on the distance between the plate and nozzle, Reynolds number and equivalence ratio (ER). The solution of the differential equation related to conservation of momentum, mass and energy has been analysed. The radiative heat transfer model has been designed using several radiation models and the turbulence model is analysed by the help of RNG k–ε turbulence model. In the response plot it is found that heat flux increases progressively with the radial distance towards the centre of the plate to achieve the maximum value at a position a bit away from stagnation point and thereafter it reduces. It has also been exhibited that when the distance of the target plate increases, the location of the maximum value of the local heat flux approaches the stagnation point. The dependence of heat transfer phenomena on ER, Reynolds number and separation of the plate from the nozzle has been studied.

Appendices

Nomenclature

C _p :

specific heat at constant pressure (kJ/kg K)

D :

diffusion coefficient (m²/s)

d :

burner diameter (m)

H :

distance of the target plate from the nozzle (m)

h :

specific enthalpy (kJ/kg)

I :

radiation intensity (kW/m²)

K :

thermal conductivity of the plate (kW/m K)

Nu :

Nusselt number

p :

pressure (Pa)

q :

heat flux (kW/m²)

R :

universal gas constant (J/mol K)

Re :

Reynolds number

R :

plate radius (m)

r :

burner radius (m)

T :

absolute temperature (K)

Greek symbols

α :

thermal diffusivity (m²/s)

$\mu$ _t :

turbulent viscosity (kg/m s)

γ :

stoichiometric air fuel ratio

μ :

dynamic viscosity (kg/m s)

k :

turbulent kinetic energy (m²/s²)

ɛ :

dissipation rate of turbulent kinetic energy (m²/s³)

ρ :

density (kg/m³)